Despite a new state law capping school property taxes at 2 percent, bills with hikes as high as 6, 10 and even more than 16 percent are landing in Long Island residents’ mailboxes like lead weights.

“It was really a shock,” said Sheri Baker of East Williston, whose tax bill jumped 16.5 percent this year.

“We were told about a 2 percent tax cap and we thought we were getting it under control,” she said. “And then the bill comes, and it’s astronomical! And no one can give me an explanation.”

The culprit is how the burden of school spending — typically the biggest expense of local government — is shared among taxpayers, officials say.

Even though a state law signed by Gov. Cuomo in June 2011 requires school boards and other local governments to cap their tax levy at 2 percent, the tax burden in Nassau is actually distributed unevenly.

So while some of the county’s taxpayers may be seeing lower bills, others — even some elected officials — are getting whopping increases.

“I heard from constituents who told me their taxes went up 9 to 10 percent, even though the state had put a cap on taxes,” said Nassau Legislator Wayne Wink (D-Roslyn).

“Then I got my bill — and my taxes went up 13 percent!” Wink said.

The law does not cover how spending increases are shared by taxpayers.

East Williston school-board president Mark Kamberg said that even though the spending increase in his district this year is the lowest in two decades, many people are still seeing whopping property-tax hikes.